The new secure AMJ format (in use since version 4.20.1) only allows sharing of the files when user specifically permitted it. To do that, please click Tools->Options->Password, then tick the "Allow Multi-user access" box and select a password (how short is your choice). This must be done on the computer where the file was originally created! So if you have reinstalled your operating system or if you want to open the file on another computer, it will not open unless you previously permitted it in AceMoney in which it was originally created. If you are unable to open the file on the original platform (because you reinstalled the operating system, or because your computer has crashed), you will have to submit a support ticket to send the file to us, so that we can reset its security settings, and send it back to you. The ticket support threads are private and safe, and we don't send the file back via the thread but directly to your email address.